"There you go, then," Duke said. "And -- I mean, as long as Lucifer doesn't go around telling people he hates us or something, he can call it what he likes, too."

Yes, Duke had absolutely had partners in the past who'd claimed to hate him when talking to other people. Not just Nathan, either. It was practically a theme of his love life, before Evi.

(It probably explained some things about his relationship with Evi, really. She gloried in calling him her husband, after all.)